Prosecutors have opened a criminal investigation into leaders of the German Green Party over coronavirus bonuses they paid themselves.

Annalena Baerbock, the foreign minister, and Robert Habeck, the vice-chancellor and business and climate minister, are among six party members under investigation.

They are being investigated on suspicion of breach of trust after they awarded themselves €1,500 (£1,245) special bonuses to cover the cost of working from home during the pandemic. If found guilty, they could face up to five years in prison or a fine.

The payments broke party rules limiting bonuses to €300 (£250). As members of the party’s national executive it was the leaders’ responsibility to uphold the rules.

The investigation was ordered after a number of members of the public filed criminal complaints over the bonuses.

But prosecutors stressed that they have only opened a preliminary investigation into whether a crime was committed.

Under German law a preliminary investigation must be opened if there is any indication a crime may have taken place.

Mr Habeck and Ms Baerbock downplayed the accusations and pledged to cooperate with the investigation.

“This chapter will soon be finally closed,” Ms Baerbock said. “The funds have already been paid back. Naturally we are fully cooperating with the investigating authorities so that the matter can quickly be cleared up.”